1. Field of the Invention
The present invention relates to a device for treating water which circulates in a closed conduit system, for instance in a central heating system.
2. Prior Art
It is known to degas or de-aerate liquid that circulates in a closed circuit, in order to inhibit corrosion and cavitation in pumps. An arrangement intended for this purpose is described, for instance, in EP-A-0 273 508. WO 97/10890 teaches a similar de-aerator arrangement connected in series and combined with an arrangement for separating solid particles from the circulating liquid. Cathodic devices are other forms of corrosion inhibiting means. For instance, U.S. Pat. No. 4,376,753 and WO 96/22407 teach the arrangement of electrolysis apparatus having consumable anodes connected in parallel conduits branching from the circulation system and particularly designed for this purpose. The arrangement can be controlled by regulating the flow of liquid passing through the parallel conduits and electrolysis apparatus, voltage selection across anode and cathode, selection of anode material and the optional addition of electrically conductive liquid, e.g. hydrazine. These corrosion inhibitors are, however, both sophisticated and expensive and are therefore inappropriate for use in central heating systems. There have also been suggested in the art corrosion inhibitors in the form of separate vessels that can be arranged in a parallel conduit or directly in the closed circuit, such that part of the liquid circulating in the circuit or all of said liquid will pass through said vessels, and which includes a sacrificial anode that functions in the absence of an applied voltage. Such inhibiting devices are commercially available under designations PROMAG(copyright) and ELYSATOR(copyright) respectively. The arrangement of a corrosion inhibiting device in a parallel conduit incurs extra installation costs and the requirement of more space, whereas the installation of a corrosion inhibiting device directly in a conduit in the closed circuit normally results in unacceptable erosion of the sacrificial anode, therewith greatly limiting the useful life span of said anode.
The present invention addresses the problem of providing a water treatment device that prevents corrosion both by de-aerating or degassing the circulating liquid and by processing the liquid electrolytically, and that is also essentially free from the drawbacks associated with known cathodic corrosion inhibitors previously mentioned.
With the intention of solving said problem, there is proposed in accordance with the invention a device of the kind defined in the introduction which is comprised of a degassifier and corrosion inhibitor combination, wherein the degassifier includes a tubular member which is horizontal in its use position and which is intended for connection in series with a conduit that forms part of the conduit system and which is surrounded between its upstream and downstream ends by an openable housing that includes an upper gas outlet, said tubular member communicating with the surrounding housing space via at least one opening provided therein, and wherein the corrosion inhibitor includes a sacrificial anode and is located in the housing space outside said tubular member, said housing also being provided with an openable bottom outlet.
The arrangement proposed in accordance with the invention provides, with the aid of simple means, an advantageous and effective water treatment device with which erosion of the sacrificial anode is very slight and with which said anode will dissolve essentially only at the rate covered by the occurring need of corrosion inhibiting. This combination of degasifier and corrosion inhibitor with sacrificial anode in one single component in accordance with the invention also affords important place-saving and simplified installation advantages.
It is an object of the invention that the anode is accommodated partially in a pipe-like member which projects out from the housing and which has an outer cover member.
Another object of the invention is that the pipe-like member extends downwardly from the housing in general, and in that the bottom drain or outlet is provided in the cover member.
A further object of the invention is that the sacrificial anode is carried by the cover member.
A still further object of the invention is that the sacrificial anode is supported electrically insulated from the cover member.
Another object of the invention is that the bottom outlet or the cover member includes a sludge outlet valve.
It is an object of the invention that either the upstream or downstream end of the tubular member is connected to a particle separator, and in that the degasifier and particle separator are housed in a common housing.
Another object of the invention is that the particle separator is connected to the upstream end of the tubular member.
These together with other objects and advantages which will become subsequently apparent reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout.